1. Field of the Invention
The instant invention relates generally to propulsion units for marine vessels and more specifically it relates to an hydraulic power system for a boat.
2. Description of the Prior Art
Numerous propulsion units for marine vessels have been provided in prior art. For example, U.S. Pat. Nos. 4,143,614 to Jeanson et al.; 4,358,280 to Jeanson et al. and 4,878,864 to Van Bentem all are illustrative of such prior art. While these units may be suitable for the particular purpose to which they address, they would not be as suitable for the purposes of the present invention as heretofore described.
The screw of a screw-rudder propulsion assembly for a floating vehicle is suspended on the end of a steering shaft which is housed in a tubular casing which is supported on the vehicle. The shaft is rotated to steer the vehicle and the screw is driven by a hydrostatic receiver unit housed in the screw-rudder assembly. A pair of rotating joints through which oil is circulated to the hydrostatic receiver unit, a trust bearing, and the steering drive for rotating the steering shaft are grouped together at the top of the shaft.
A screw-rudder assembly is mounted at the bottom of a steering shaft which rotates in a tubular casing which is mounted on slide shoes which slide in vertical slide guides fixed to a support which is mounted on a floating vehicle. A power cylinder connects the tubular casing to the support and slides the casing upwardly to regulate the depth of immersion of the screw and pivots the casing upwardly about upper slide shoes when bottom slide shoes are released through passages in the slide guides, to lift the screw-rudder out of the water.
A new and improved compass-type retractable marine thruster apparatus comprises a housing pivotally mounted on a base that can be attached to the stern of a vessel. A tubular member has an upper section extending into the housing. A hub is attached to the lower end of the tubular member. A cross-vane hydraulic motor is in the hub and has a propeller mounted directly on its output shaft. A swivel assembly at the top of the tubular member is arranged so that oil under pressure can be fed to a plurality of lines that are connected to the motor. A steering motor is for rotating the tubular member about its longitudinal axis. An hydraulic cylinder can be extended to pivot the tubular member, hub and propeller out of the water.